Quantitative 13C NMR requires full relaxation of all carbons at each scan, which is typically very long (could mean that you have to set d1 to > 100 seconds).  Adding paramagnetic chemicals could speed up the relaxation.  A common choice is chromium acetylacetonate, or Cr(acac)3.  The trick is to add a suitable amount to your … Continue reading How to run quantitative 13C and 29Si NMR faster